In general, the procedure for assembling a multiple glazed structure involves placing one sheet of glass over the other in a fixed, spaced relationship, and then injecting a sealant composition into the space between the two sheets of glass, at and along the periphery of the two sheets, thereby forming a sandwich structure having a sealed air pocket.
Heretofore the means employed for maintaining the spacing between the sheets of glass was either of a temporary, removable nature, or of a permanent nature. Exemplary of temporary removable spacer means are those disclosed in U.S. Pat. Nos. 2,275,812 and 3,097,061. U.S. Pat. Nos. 3,758,996 and 4,113,905 show embodiments of permanently installed spacer means. U.S. Pat. No. 3,758,996 also teaches the concept of incorporating a desiccant within the spacer means. The desiccant functions as a medium upon which moisture and organic materials in the sealed air pocket are sorbed. This prevents the moisture from condensing on and fogging the interior surfaces of the sheets of glass.
In practicing the teachings of the prior art, multiple steps are required. Where a removable spacer means is employed, the spacer means must be set in place, the sealant injected, the sealant cured, and the spacer means thereafter removed. Where a permanent spacer means is employed, an adhesive is applied to secure the permanent spacer to the glass sheets, the spacer is then set in place, and a sealant is then injected into the peripheral channel formed between the spacer and the edges of the sheets of glass.
These prior art practices are cumbersome, labor intensive and expensive, and are believed to have been instrumental in limiting the fabrication of energy saving, thermal insulating multiple glazing structures to factory assembly, and the installations thereof, to situations where cost effectiveness is established by very high energy costs.
Clearly, the prior art practices do not readily lend themselves to on-the-job assembly, as is, for example required in retrofitting single glazed structures to thermal insulating multiple glazed structures. U.S. Pat. No. 3,573,149 describes a rather complex prior art procedure for forming double glazed windows which can be used in retrofit applications. The procedure involves the use of a spacer member in which is embedded a resistance wire, and to which is appended a tubular member containing desiccant. The procedure involves cutting the thermo-electric spacer and sealing strip to the peripheral length of the panel with sufficient extra length to form electrical terminals for connection to a power supply source, unsheathing the ends of the resistance wire passing through the strip and applying an electric potential thereto to heat the strip until it becomes pliable, applying the strip to the perimeter of one panel, reapplying an electric potential to the resistance wire to soften the strip, aligning a second panel and pressing the panels together, again applying an electric potential to cure the strip, and trimming off the ends of the strip.
In addition to being a cumbersome and undoubtedly expensive procedure, it should be noted that the thermo-electric spacer and sealing strip employed in the patented arrangement does not provide any means for positively maintaining a predetermined space between the panels. Indeed, the patentees state that the glass panes are gently but firmly pressed together until the sealing strip "shows a black vitreous effect all around."
Other references, of general interest in showing the state of the art are U.S. Pat. Nos. 2,695,430 and 3,045,297, and British Pat. No. 605,234 all of which show use of various rigid spacer members and separators for multiple pane window units, luminous panels and the like.
Against this background of cumbersome, inefficient methodology, and multicomponents materials and structures for assembling multiple glazing structures, the present invention contributes to the art a unitary, multipurpose structure which functions as a sealant and spacer, and optionally a desiccant, the use of which in assembling multiple glazing structures simplifies the methodology, reduces costs and permits assembly to be conducted on-site as a retrofit acitivity, or in a factory, with equal facility. Moreover, the use of the single unitary structure of the present invention substantially reduces the labor and materials costs involves in assembling multiple glazing structures, thereby making such installations cost effective against lower energy costs than is the case with more expensive prior art materials and procedures.